The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
AAA authentication, authorization, and accounting
AP access point
BSS basic service set
BSSID basic service set identifier
EAP extensible authentication protocol
EAPOL extensible authentication protocol over LANs
ESS extended service set
FCS frame check sequence
GAS generic advertisement service
LAN local area network
MAC/PHY media access control/physical
RTT round trip time
SSPN subscription service provider network
STA station
Wireless networking using the 802.11 protocol, commonly referred to as Wi-Fi, is widely used, with many entities such as governments, businesses, transit services, libraries, airports, museums, and airlines providing wireless networking access either free of charge or for a fee. The wider availability of data services through subscription networks, such as 3G and 4G networks, has not reduced the demand for 802.11 protocol services. Indeed, the proliferation of 3G and 4G networks has increased the number of devices that are capable of using 802.11 services, because devices using 3G and 4G networks provide data capability and it is a simple matter to design such devices so that they can also take advantage of 802.11 services. Such devices are typically small and easily carried everywhere. In addition, many larger, but still small, devices are now available, and many such devices typically employ 802.11 services and do not use 3G or 4G services. Both small devices such as wireless telephones and similar devices, and larger devices, such as tablets or readers, may be carried everywhere by a user—to restaurants, to cafés, on buses, on the street, to airports, on airplanes, and at many other locations. A user of a 3G/4G device might choose to use available 802.11 services for any of a number of reasons. For example, the user might be receiving a poor signal or might be traveling outside of his or her home network. Selecting 802.11 services might provide the user with a connection that is fast, reliable, and inexpensive or even free of charge.
Many small devices have limited battery power, and many such devices may be used under circumstances in which it is difficult to charge the device. For example, if a device is used on a bus or an airplane, the user may well need to depend on the battery charge that was present when the user boarded the vehicle, without an opportunity to recharge possibly for hours.
The proliferation of small devices has increased the use of data communication while users are moving from one location to another. One significant factor that reduces the usefulness of data devices under such circumstances is the time required for connection of a client to an access point. Faster connections reduce power consumption and make it easier for users to continue their activities when moving between areas served by different access points.